A Researcher Wanted to Determine If Using an Octane Booster

question 11

Multiple Choice

A researcher wanted to determine if using an octane booster would increase gasoline mileage. A random
sample of seven cars was selected; the cars were driven for two weeks without the booster and two weeks
with the booster.
$$\begin{array} { | l | l | } \hline \text { Miles / Gal Without } & \text { Miles / Gal With } \\\hline 21.2 & 23.8 \\\hline 25.4 & 25.6 \\\hline 20.9 & 22.4 \\\hline 27.6 & 28.3 \\\hline 22.8 & 24.5 \\\hline 27.3 & 28.8 \\\hline 23.4 & 25.2 \\\hline\end{array}$$
-A dietician investigated whether apples turned brown at different rates when exposed to air after being washed in hot water or in cold water. She took 12 random apples and cut each in half. She washed one
Half of each apple in hot water and the other half in cold water, and then put both halves out in a tray. Her
Results (in hours until turning a particular shade of brown) are in the table below. At , did she see a
Difference between the two treatments? $$\begin{array} { | l | c | c | c | } \hline & \text { Hot Water } & \text { Cold Water } & \begin{array} { c } \text { Difference } \\\text { by Apple }\end{array} \\\hline \text { Sample mean } & 6.00 & 5.95 & - 0.05 \\\hline \text { Sample variance } & 2.10 & 2.50 & 0.65 \\\hline\end{array}$$

• A) No, because the test value -0.06 is inside the range (-3.05, 3.05).
• B) No, because the test value -0.21 is inside the range (-3.11, 3.11).
• C) No, because the test value -0.21 is inside the range (-3.05, 3.05).
• D) No, because the test value -0.06 is inside the range (-3.11, 3.11).

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Definitions:

Cotton Gin

Invented by Eli Whitney in 1793, the machine that separated cotton seed from cotton fiber, speeding cotton processing and making profitable the cultivation of the more hardy, but difficult to clean, short-staple cotton; led directly to the dramatic nineteenth-century expansion of slavery in the South.

Eli Whitney

An American inventor best known for inventing the cotton gin, a device that revolutionized the cotton industry.

Boll Weevil

A beetle that feeds on cotton buds and flowers, historically significant for its devastating impact on the United States cotton industry.

Mid-Nineteenth Century

Refers to the period approximately from 1830 to 1870, a time marked by significant historical events including the American Civil War.